The present invention relates to an articulated robot, which has a plurality of articulations and whose front end is automatically moved to predetermined object positions so as to execute jobs.
Articulated robots are installed in factories. A front end of each articulated robot is moved to prescribed positions so as to automatically execute welding, grinding, abrading, assembling, transporting, etc..
To automatically and efficiently execute such jobs, an optimum moving track of the robot is previously inputted to the robot. This step is called “teaching”.
There are several methods of teaching actions. For example, an operator manually moves an arm section of the articulated robot to prescribed positions to teach a moving track (see Japanese Patent Gazette No. 2001-341092). This type is well known and suitable for quickly moving a light arm section. But, if the arm section is heavy, it is hard for the operator to move the arm section to object positions. Further, precise adjustment is difficult.
In some machining robots, teaching is executed by using a switch of an operation panel. Namely, an arm section is moved in an assigned direction as far as the operator pushes the switch (see Japanese Patent Gazette No. 10-146782). Even if the arm section is heavy, the operator is capable of easily executing the teaching action. However, the operator must turn on and off the switch many times so as to precisely move the arm section to object positions. Therefore, it takes a long time to correctly teach the arm section. Further, it is difficult to precisely position the front end by the switch. In some cases, the arm section collides with a work to be machined.
Further, in some robots, teaching is executed by inputting pulses, which are generated by a pulse generator. Namely, the arm section is moved a distance corresponding to number of inputted pulses (see Japanese Patent Gazette No. 9-198122). However, the operator must adjust a rotational angle of each articulation. Each articulation can be precisely controlled, but it is difficult to simultaneously control all articulations to correctly move the arm section. Therefore, this type is not practically used.
In some cases, the arm section may be roughly and quickly moved to one position, then it should be precisely moved to another position so as to efficiently move the arm section. However, in the conventional methods, actions of the arm sections are fixed.